US-Mexico drug tunnel

View Gallery

A federal agent crawls through a 600-yard tunnel discovered in a warehouse along the border between the United States and Mexico in Otay Mesa, a suburb of San Diego, Calif., on Nov. 3. Agents recovered more than 20 tons of marijuana during overnight searches of the tunnel, the border patrol said in a news release. U.S. Immigration and Customs Enforcement/AP

John Morton (l.), the director of Immigration and Customs Enforcement, points out the opening of a 600-yard tunnel to Joe Garcia, assistant agent in charge for Homeland Security Investigations, in a warehouse where 20 tons of marijuana were seized in Otay Mesa, Calif., on Nov. 3. Lenny Ignelzi/AP

John Morton (l.), director of US Immigration and Customs Enforcement, looks at blocks of marijuana inside a warehouse near the Mexican border where a 600-yard tunnel between the US and Mexico was found, along with 20 tons of marijuana, in Otay Mesa, Calif., on Nov. 3. Nelvin C. Cepeda/San Diego Union-Tribune/Reuters

An open bundle of marijuana is part of 20 tons of marijuana seized near a tunnel at a warehouse along the border between the US and Mexico in Otay Mesa, Calif., on Nov. 3. Lenny Ignelzi/AP

A federal agent stands guard near a truck with 10 tons of marijuana outside a warehouse along the border between the US and Mexico where 20 tons of marijuana were seized in Otay Mesa, Calif., on Nov. 3. A 600-yard tunnel was discovered in the warehouse. Lenny Ignelzi/AP

On the Mexican end of a tunnel found between Tijuana and Otay Mesa, Calif., a soldier guards a warehouse near the US-Mexican border in Tijuana, Mexico, on Nov. 3. Guillermo Arias/AP

Soldiers guard a warehouse where a tunnel was found near the US-Mexican border in Tijuana, Mexico, on Nov. 3. Guillermo Arias/AP

A soldier guards packages of marijuana during a presentation to the media in Tijuana, Mexico, on Nov. 3. The Army reported that 9,898.75 pounds of marijuana were seized from a tunnel found near the US-Mexican border in Tijuana, Mexico, on Nov. 3. Guillermo Arias/AP

In an apparent double blow to Mexico's most notorious drug cartel, Mexican authorities said they believed they have killed the leader of the Zetas gang and captured a high-ranking lieutenant wanted for more than 300 murders.